Using specially designed submicroscopic capsules in tests on rats, scientists have neutralized the deadly toxin released by the bacterium that causes anthrax. Although antibiotics can kill the microbe, there is currently no means of eliminating the toxin once it's unleashed in a person's body.
When Bacillus anthracis infects a mammal, it secretes three proteins that together prove lethal. One of the proteins, called protective antigen (PA), acts as the scout, latching on to a cell. That bond enables the other two anthrax-toxin proteins to enter the cell and kill it.
Because it's the linchpin for cell invasion, PA is an obvious target for antianthrax drugs. Some synthetic compounds had shown promise in binding to PA and blocking the toxin's lethal effect (SN: 10/6/01, p. 212: Chemical Neutralizes Anthrax Toxin).